For painting motor vehicle body components, rotary atomisers, which atomise the paint to be applied using a rotating bell cup, are usually used. Although conventional rotary atomisers are well-suited for painting the full surface of components, the application of stripes or other patterns, and also the coating of partial surfaces therewith is problematic.
It is likewise known to use what are called droplet generators for coating components, as is described for example in DE 10 2010 019 612 A1. Therein, the coating agent to be applied is passed through a perforated plate with numerous through-holes, with a coating-agent jet emerging in each case from the individual through-holes in the perforated plate, the jet breaking up into droplets which then impinge on the component surface to be coated and form there a coherent coating-agent film.
What is problematic about this known droplet generator is the fact that the perforated plate has wetting surfaces at the hole exits which are partially wetted by the emerging coating agent during operation, which prevents the coating-agent jet from being detached from the perforated plate.
Furthermore, with perforated plates according to the prior art there is the problem that the necessary coating-agent volume flow is not achieved because the hole diameters are too small and the thickness of the perforated plate is too great to overcome the pressure loss occurring with coating agents of conventional viscosities. If the thickness of the perforated plate is reduced, it will however lose its mechanical stability.
A nozzle plate for an inkjet printer is known from DE 691 23 224 T2, but this known nozzle plate cannot be used in the field of application technology.
Furthermore, with regard to the prior art reference should be made to EP 0 928 637 A2, DE 10 2004 030 640 A1, DE 20 2011 000 324 U1 and DE 40 21 661 C2.